Feasibility of fractal dimension analysis for left ventricular trabecular complexity using cardiac computed tomography

Aims: To evaluate the consistency between fractal dimensions (FD) derived from cardiac computed tomography (CT-FD) and cardiac magnetic resonance (MR-FD) in assessing left ventricular trabecular complexity.

Methods: This retrospective study included 170 patients who underwent CCT and CMR scans within two weeks. Five short-axis cine images were selected at end-diastole: one basal, three mid, and one apical slice. Short-axis CCT views were reconstructed and aligned with the cine images. CT-FD and MR-FD values were calculated for each slice, with mean values determined for each patient. Severe left ventricular hypertrophy (LVH) was defined as a maximum wall thickness > 15 mm in end-diastolic cine images.

Results: The diastolic CT-FD and MR-FD values exhibited high consistency, with values of 1.253 ± 0.091 and 1.250 ± 0.102, respectively (n = 535, ICC = 0.882, 95 % CI: 0.861-0.899, P < 0.001). Similarly, the systolic CT-FD and MR-FD values demonstrated good consistency, with values of 1.268 ± 0.072 and 1.286 ± 0.093, respectively (n = 390, ICC = 0.720, 95 % CI: 0.669-0.765, P < 0.001). For subgroups of systolic NLVH and LVH, the ICCs were 0.773 (n = 305, CI: 0.723-0.814, P < 0.001) and 0.565 (n = 85, 95 % CI: 0.402-0.694, P < 0.001), respectively. The diagnostic efficacy of mean CT-FD aligned with that of mean MR-FD in distinguishing abnormal cardiac conditions from the CMR-negative group.

Conclusions: CCT is a feasible method for assessing left ventricular trabecular complexity, with good agreement with CMR, except in cases of severe left ventricular hypertrophy during systole.